1. Field of the Invention
The present invention relates to a burnishing method and a burnishing apparatus and to a burnishing method which is suitably used when performing surface polishing for finish of a magnetic disk which is used in, for example, a hard disk drive.
Priority is claimed on Japanese Patent Application No. 2012-138576 filed on Jun. 20, 2012, the contents of which are incorporated herein by reference.
2. Description of Related Art
The distance between a magnetic disk and a magnetic head which floats and runs on the magnetic recording surface of the magnetic disk becomes increasingly narrow with an increase in the recording density of the magnetic disk which is used in a hard disk drive. For this reason, it is necessary to reduce the flying height of the magnetic head.
Further, in the past, in a manufacturing process of the magnetic disk, burnishing (polishing treatment) to remove minute dust or projections formed on or stuck to the surface of the magnetic disk has been performed. Since the smoothness of the surface of the magnetic disk is improved by performing the burnishing, the flying height of the magnetic head in the hard disk drive can be further reduced.
As a burnishing method of the related art, for example, a method to press a polishing tape against the surface of the magnetic disk which rotates, by a contact roller, and run the polishing tape with respect to the surface of the magnetic disk can be given (refer to, for example, Japanese Unexamined Patent Application, First Publication No. H11-277339).
Usually, the polishing tape which is used in the burnishing spans between a supply reel and a take-up reel, sequentially supplied from the supply reel, and then taken up by the take-up reel. Then, on the way where the polishing tape runs from the supply reel side to the take-up reel side, the surface (the back surface) on the opposite side to an abrasive grain surface of the polishing tape is pressed by the contact roller, and thus the polishing surface is pressed against the surface of the magnetic disk.
As the polishing tape (a burnishing tape) which is used in the burnishing, usually, a tape made by forming an abrasive layer on a base film made of polyester is used. As an abrasive, chromium oxide, α-alumina, silicon carbide, nonmagnetic iron oxide, diamond, γ-alumina, α,γ-alumina, molten alumina, corundum, artificial diamond, or the like, which has an average particle diameter in a range of 0.05 μm to 50 μm, is used (refer to, for example, Japanese Unexamined Patent Application, First Publication No. H09-054943).
Further, also in Japanese Unexamined Patent Application, First Publication No. 2010-267313, a burnishing process for the surface of the magnetic disk is described. In the burnishing process described in Japanese Unexamined Patent Application, First Publication No. 2010-267313, after a burnishing tape is loaded on a ramp road provided further outside the outermost periphery of the magnetic disk, processing is performed by moving the tape on the surface of the magnetic disk, and thereafter, the tape is unloaded from the ramp road.